Extraction of arsenic in solution in liquors containing alkali metal carbonate, sulphate and possibly hydroxide, and at least one of the metals vanadium, uranium and molybdenum
US4495159A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 16, 1982 |
| Grant date | Jan 22, 1985 |
| Priority date | — |
| Expiry date | Jul 16, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/80
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for extracting arsenic from aqueous solution to be purified, in accordance with claim 1 of U.S. Pat. No. 2,404,601, which also contains alkali metal carbonate, sulphate, hydroxide or hydrogen carbonate, and which may also contain at least one of the metals vanadium, uranium and molybdenum, comprising caustification of said solutions by means of lime to convert the carbonates into alkali metal hydroxides, followed by separation of an alkali metal hydroxide-enriched liquor and a first precipitate essentially containing calcium carbonate which is subjected to a washing operation, concentration by evaporation of the mixture of the washing liquor of the first precipitate to produce a second precipitate which essentially comprises alkali metal sulphate, which is characterized in that, before the aqueous solution is caustified, the aqueous solution is treated by a magnesium compound in an amount at least equal to the stoichiometric amount required to cause precipitation of magnesium arsenate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.